This invention relates generally to improvements in automatic pool cleaning devices designed for travel over submerged floor and sidewall surfaces of a swimming pool or the like to pick up and collect accumulated debris such as leaves, twigs, sand and silt. More particularly, this invention relates to an improved pool cleaner of the so-called suction or vacuum powered type, having means for cyclic interruption of water flow to generate pulsating forces which cause the pool cleaner to advance in steps over submerged pool surfaces. The present invention is particularly directed to an improved control valve having magnet means for improved oscillatory movement to interrupt the water flow and thereby generate the requisite pulsating forces to drive the cleaner over submerged pool surfaces.
Pool cleaner devices are generally well known in the art for use in maintaining residential and commercial swimming pools in a clean and attractive condition. In this regard, swimming pools conventionally include a water filtration system including a pump for drawing or suctioning water from the pool for circulation through a filter canister having filter media therein to remove and collect water-entrained debris such as leaves and twigs as well as fine particulate including sand and silt. From the filter canister, the water is recirculated to the pool via one or more return lines. Such filtration system is normally operated for several hours on a daily basis and serves, in combination with traditional chemical treatments such as chlorination or the like, to maintain the pool water in a clean and clear sanitary state. However, the water filtration system is ineffective to filter out debris which settles onto submerged floor and side wall surfaces of the swimming pool. In the past, settled debris has typically been removed by coupling a vacuum hose to the suction side of the pool water filtration system, such as by connecting the vacuum hose to a skimmer well located near the water surface at one side of the pool, and then manually moving a vacuum head coupled to the hose over the submerged pool surfaces to vacuum settled debris directly to the filter canister where it is collected and separated from the pool water. However, manual vacuuming of a swimming pool is a labor intensive task and is thus not typically performed by the pool owner or pool cleaning service personnel on a daily basis.
Automatic pool cleaner devices have been developed over the years for cleaning submerged pool surfaces, thereby substantially eliminating the need for labor intensive manual vacuuming. Such automatic pool cleaners typically comprise a relatively compact cleaner housing or head coupled to the pool water filtration system by a hose and including water-powered means for causing the cleaner to travel about within a swimming pool to dislodge and collect settled debris. In one form, the pool cleaner is connected to the return or pressure side of the filtration system for receiving positive pressure water which powers a turbine or the like for rotatably driving cleaner wheels, and also functions by venturi action to draw settled debris into a filter bag. See, for example, U.S. Pat. Nos. 3,882,574; 4,558,479; 4,589,986; and 4,734,954. In another form, the pool cleaner is coupled to the suction side of the filtration system, whereby water is drawn through the pool cleaner to operate a drive mechanism for transporting the cleaner within the pool while vacuuming settled debris to the filter canister of the pool filtration system. See, for example, U.S. Pat. Nos. 3,803,658; 4,023,227; 4,133,068; 4,208,752; 4,351,077; 4,642,833; 4,742,593; 4,761,848; 4,769,867; 4,807,318; 5,265,297; 5,315,728; 5,450,645; and 5,634,229.
While both positive pressure and suction powered pool cleaners have proven to be generally effective in cleaning settled debris and the like from submerged pool surfaces, various customer preferences and installation considerations have been instrumental in causing an individual customer to choose one cleaner type over the other. For example, by comparison, positive pressure type cleaners are generally regarded as providing better collection of large debris such as leaves in a removable filter bag, to prevent such large debris from being drawn into and potentially clogging the filter canister of the pool water filtration system. However, such positive pressure cleaners often require a booster pump and/or installation of an additional dedicated water return line to be integrated into the filtration system, whereby the overall cost of installing a positive pressure cleaner particularly in an existing pool can be significant. By contrast, a suction side cleaner can often be coupled by a vacuum hose directly into the existing skimmer well of a pool, for relatively simplified connection to the suction side of the filtration system in a pool that is not equipped with a pre-installed suction side cleaner flow line. Moreover, suction side cleaners are designed for operation without requiring an additional booster pump. Accordingly, suction side cleaners have tended to be somewhat less costly to install, in comparison with pressure side cleaners.
Most suction side cleaners currently available on the market utilize a valve member typically in the form of a diaphragm or shuttle type valve adapted for movement between open and closed positions at a cyclic rate to disrupt the suction flow in a manner creating pressure surges or pulsations of sufficient magnitude to propel the cleaner in a forward direction over submerged pool surfaces in a series of incremental steps. However, this valve member has been susceptible to clogging upon ingestion of debris vacuumed from a submerged pool surface. Clogging of the valve member not only results in undesirable stalling or interruption in cleaner operation, but also creates a risk of cavitation and potential failure of the filtration system pump.
U.S. Pat. No. 6,112,354 discloses an improved suction powered pool cleaner having an oscillatory valve member for generating the requisite pressure surges to drive the pool cleaner over submerged pool surfaces, but wherein the valve member swings to an open position substantially out of alignment with the debris and water flow path to minimize the risk of clogging. In this design, the valve member is mounted for oscillatory movement between the open position and a substantially but preferably incomplete closed position relative to an upstream end of a suction tube through which debris and water are vacuumed, with a spring biasing the valve member toward the open position. The suction flow through the suction tube draws the spring-loaded valve member toward the closed position to achieve momentary substantial interruption of the water flow, accompanied by an increasing spring force which eventually urges the valve member to swing back toward the open position thereby resulting in oscillatory valve member movement and generation of the desired pressure surges to drive the cleaner within the swimming pool.
The present invention provides further improvements in pool cleaners of the suction powered type, particularly of the type described in U.S. Pat. No. 6,112,354, and more particularly with respect to providing an improved control valve oscillatory drive means for generating the requisite pressure fluctuations or surges to propel the cleaner over submerged pool floor and side wall surfaces. The present invention fulfills these needs and provides further related advantages.
In accordance with the invention, an improved oscillatory control valve is provided in a suction powered pool cleaner such as the pool cleaner disclosed in U.S. Pat. No. 6,112,354 for vacuuming dirt and debris from submerged floor and side wall surfaces of a swimming pool or the like. The improved control valve is mounted at the upstream end of a suction tube for movement between an open position and a substantially closed position to substantially interrupt the water flow through the suction tube in a cyclic manner and thereby produce a succession of pressure fluctuations or pulsations effective to drive the pool cleaner over submerged pool surfaces in a series of small steps. Oscillatory driving of the control valve is assisted by permanent magnets which generate repulsion forces as the valve approaches the open and closed positions, respectively, to reverse the direction of control valve movement.
In a preferred form, the suction powered pool cleaner comprises a compact housing or head adapted for connection to a vacuum hose or the like coupled in turn to the suction side of a conventional pool water filtration system. The cleaner head defines a suction inlet through which water and debris are drawn from an underlying pool surface for flow to the vacuum hose. A flexible perforated mat or disk is carried by the cleaner head to extend radially outwardly therefrom in surrounding relation to the suction inlet. Water is drawn radially inwardly beneath as well as downwardly through the perforated disk to sweep dirt and debris from the underlying pool surface for flow through the suction inlet into a plenum chamber formed within the cleaner head. From the plenum chamber, the water and entrained debris are drawn further through the suction tube and the vacuum hose to the pool water filtration system.
The control valve is mounted within the plenum chamber of the cleaner head, generally at an upstream end of the suction tube, for oscillatory movement between an open position retracted substantially from and disposed generally out of alignment with the suction tube, and a substantially closed position overlying the upstream end of the suction tube for substantially obstructing water flow from the plenum chamber to the suction tube. In the preferred form, the control valve comprises a valve member mounted for pivotal swinging movement between the open and substantially closed positions.
At least one permanent magnet is mounted on or otherwise carried for movement with the valve member between the open and closed positions. This valve member magnet is positioned for movement respectively into general alignment and/or magnetic interaction with at least one first and second stationary permanent magnets mounted on the cleaner head, upon valve member movement respectively to the open and closed positions. Importantly, these permanent magnets are oriented with like poles presented toward each other, so that magnetic repulsion forces are generated as the valve member moves toward the open and closed positions. The valve member is thus magnetically biased to a normal or neutral position generally mid-way between the open and closed positions.
In operation, suction water flow from the plenum chamber into the suction tube draws the valve member toward the substantially closed position. As the valve member approaches the closed position, the valve member magnet approaches the at least one associated stationary magnet with resulting increase in repulsion force which, in combination with the interrupted water flow, ultimately overcomes the suction force to reverse the direction of valve member movement. The valve member then swings back past the neutral position and toward the open position with the valve member magnet approaching the opposite at least one stationary magnet with resulting increase in repulsion force which again ultimately reverses the direction of valve member movement. Thus, the permanent magnets drive the valve member through an oscillatory motion which cyclically interrupts the water flow through the suction tube to generate the repeated pressure pulsations for driving the pool cleaner over submerged pool surfaces.
Other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.